Nuprl Lemma : decidable__l_disjoint
∀[A:Type]. ((∀x,y:A.  Dec(x = y ∈ A)) ⇒ (∀L1,L2:A List.  Dec(l_disjoint(A;L1;L2))))
Proof
Definitions occuring in Statement : 
l_disjoint: l_disjoint(T;l1;l2), 
list: T List, 
decidable: Dec(P), 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
implies: P ⇒ Q, 
all: ∀x:A. B[x], 
member: t ∈ T, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
prop: ℙ, 
decidable: Dec(P), 
or: P ∨ Q, 
append: as @ bs, 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
top: Top, 
so_apply: x[s1;s2;s3], 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
rev_implies: P ⇐ Q, 
uiff: uiff(P;Q), 
uimplies: b supposing a
Lemmas referenced : 
list_induction, 
all_wf, 
list_wf, 
decidable_wf, 
l_disjoint_wf, 
equal_wf, 
l_disjoint_nil, 
not_wf, 
nil_wf, 
list_ind_cons_lemma, 
list_ind_nil_lemma, 
append_wf, 
cons_wf, 
and_wf, 
l_member_wf, 
decidable__and2, 
decidable__not, 
decidable__l_member, 
decidable_functionality, 
iff_weakening_uiff, 
l_disjoint_append2, 
l_disjoint_singleton2
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
thin, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality, 
hypothesis, 
independent_functionElimination, 
rename, 
because_Cache, 
dependent_functionElimination, 
universeEquality, 
inlFormation, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
productElimination, 
independent_pairFormation, 
independent_isectElimination
Latex:
\mforall{}[A:Type].  ((\mforall{}x,y:A.    Dec(x  =  y))  {}\mRightarrow{}  (\mforall{}L1,L2:A  List.    Dec(l\_disjoint(A;L1;L2))))
Date html generated:
2016_05_14-PM-02_22_19
Last ObjectModification:
2015_12_26-PM-04_27_09
Theory : list_1
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